What structure forms during angiosperm fertilization but does not form during fertilization among other types of plants?

The answer is 'triploid cell'. 

This occurs when two sperm nuclei reach the interior of a female gametophyte, where one sperm will fertilise the egg cell to form a zygote, whereas the other usually fuses with the binucleate central cell, forming a primary endosperm cell, effectively constituting an organism separate from the growing embryo. Approximately 70% of angiosperm species have polyploid endosperm cells which are typically triploid (containing three sets of chromosomes), but can vary widely from diploid(2n) to 15n.

Humans can affect weathering and erosion in several ways.  humans cause  increases in acid rain and pollution, which increase the amount of  weathering  agents in the air and water, and then on land.for an easy answer: 1) acid rain2) pollution

only b